The use of lithium silicate glass ceramic has been proven in the field of dental technology because of its strength and biocompatibility. The strength can additionally be increased through the addition of a stabilizer from the group zirconium oxide, hafnium oxide, or mixtures thereof, to the starting substances (DE 10 2009 060 274 A1, WO 2012/175450 A1, WO 2012/175615 A1, WO 2013/053865 A2, EP 2 662 342 A1).
Lithium silicate glass ceramic materials, in particular when a blank contains lithium metasilicate as the main crystal phase, enable machine working without difficulty, without substantial wear of the tool. To increase strength heat treatment is then applied to convert the lithium metasilicate at least in part into lithium disilicate (DE 197 50 794 A1, DE 103 36 913 B4).
To manufacture dentures it is known to press plasticized ceramic material in a mold cavity present in a curable embedding mass (EP 1 484 031 B1, EP 0 231 773 A1).
DE 10 2007 011 337 A1 relates to veneer ceramics for dental restorations in which frame work ceramic is made of yttrium-stabilized zirconium dioxide. The main crystal phase of the ceramic comprises lithium disilicate. Lithium aluminum silicate is added.
US 2015/0274581 A1 relates to glass ceramic compositions having a combination of lithium disilicate and spodumene as crystalline phases.
A lithium silicate crystallized glass according to EP 3 059 214 A1 contains lithium metasilicate, lithium disilicate, lithium phosphate, cristobalite, tridymite, quartz, or spodumene.
When using lithium silicate glass ceramic sometimes the disadvantage is given, that the components influencing the strength could crystallize with the result, that the aesthetic is affected.